The ever-increasing demand for smaller sized mobile devices, such as cell phones, digital cameras, etc. correspondingly triggered a growing need for a smaller sized photography module, comprising elements such as an optical imaging lens, a module housing unit, and an image sensor, etc., contained therein. Size reductions may be contributed from various aspects of the mobile devices, which includes not only the charge coupled device (CCD) and the complementary metal-oxide semiconductor (CMOS), but also the optical imaging lens mounted therein. When reducing the size of the optical imaging lens, however, achieving good optical characteristics becomes a challenging problem.
Most conventional optical imaging lens are constructed with an optical imaging lens having four lens elements. The number of the lens elements in such conventional optical imaging lens is few enough for limiting the length of the optical imaging lens in a certain range. However, in light of more and more high-end products released, optical imaging lenses with more pixels to provide better imaging quality are more desirable now. This trend pushes the development of high-end products, such as optical imaging lenses constructed with an optical imaging lens having six lens elements. Both U.S. Pat. No. 7,663,814 and U.S. Pat. No. 8,040,618 disclosed an optical imaging lens constructed with an optical imaging lens having six lens elements, wherein the length of the optical imaging lens reaches 21 mm, and this is too long for smaller sized mobile devices. Therefore, there is needed to develop optical imaging lens which is capable to place with six lens elements therein, with a shorter length, while also having good optical characters.